Equivalent circuit for a split 2Meg pot - Printable Version
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+--- Thread: Equivalent circuit for a split 2Meg pot (/showthread.php?tid=17906)
Equivalent circuit for a split 2Meg pot - cpollock - 02-06-2018
I'm restoring a 38-7, and the original 2Mohm volume control/loudness circuit was replaced by a very cheap non-split pot that is falling apart. I'm embarrassed to be asking this, but I came across a thread somewhere in this forum about an equivalent circuit for the loudness control that could be constructed using two 1 Meg pots. I've got the pots now, but of course in the meantime I can't find that link. Can anyone direct me to the thread that showed a simple circuit for the loudness/volume control that was made from 2 coupled 1M pots?
I'll post an update on how well it works if I can find it again.
Thanks!!
RE: Equivalent circuit for a split 2Meg pot - Radioroslyn - 02-06-2018
Don't know how that could work but I take it that you have a dual 1m pot on hand? If so it's important to determine the taper (needs to be audio taper). If you don't have one I'd get Mark Opatt a call more than likely he can fix you up with the proper control.
GL
RE: Equivalent circuit for a split 2Meg pot - cpollock - 02-06-2018
Audio taper! Bummer, I got a pair of linears. I am doing this project to learn about tube radios, and the most effective way to learn is to make mistakes, so I'm learning a lot. I will get in touch with Mark.
In the meantime I went back and looked at my history to find the circuit. It was described in the UK Vintage Radio site. The link to the circuit is here. The circuit uses two coupled 1M pots, and provides a pretty nice Bass boost at low volume. And, of course, it uses log pots. I'll pursue this and let you know how the 38-7 likes it.
https://www.vintage-radio.net/forum/showthread.php?t=126515
Clif
RE: Equivalent circuit for a split 2Meg pot - jcassity - 02-06-2018
i stole this quote from ARF , in someones sig if it helps you at all.
“Experience is what you gain when the results aren't what you were expecting”